BY-COVID - WP5 - Baseline Use Case: COVID-19 vaccine effectiveness assessment

Matching cases to controls (1:1) and assessing covariate balance after matching

Covariate balance is the extent to which the distribution of covariates is similar across the intervention groups.

Standardized mean differences

The Standardized Mean Difference (SMD) represents a standardized difference in mean between contrasted intervention groups for each covariate.

Means intervention group Means control group Standardized mean difference
distance 0.89839344 0.89700714 0.125175777
age_cd 11.59381714 11.58271865 0.003749979
sex_cd 1.46657914 1.48366702 -0.031811299
residence_area_cd731 0.13965147 0.14646997 -0.019671111
residence_area_cd732 0.14108379 0.12961012 0.032960105
residence_area_cd733 0.71926474 0.72391992 -0.010359603
institutionalized_blTRUE 0.02781093 0.02950474 -0.010301042
foreign_blTRUE 0.15170685 0.12961012 0.061596004
pregnancy_blTRUE 0.01181666 0.02107482 -0.085675800
essential_worker_blTRUE 0.02757221 0.02845100 -0.005366853
comorbidities_blTRUE 0.45977560 0.47523709 -0.031023533
immunestatus_blTRUE 0.28037718 0.26343519 0.037717288
Means intervention group Means control group Standardized mean difference
distance 0.50039405 0.49960595 0.055113115
age_cd 11.58454344 11.56153089 0.007782637
sex_cd 1.46431208 1.45274428 0.021522477
residence_area_cd731 0.13942899 0.14398228 -0.013144831
residence_area_cd732 0.14078267 0.12441546 0.047059651
residence_area_cd733 0.71978833 0.73160226 -0.026305642
institutionalized_blTRUE 0.02768890 0.02695053 0.004500067
foreign_blTRUE 0.15185823 0.15148905 0.001028705
pregnancy_blTRUE 0.01193699 0.01021413 0.015863954
essential_worker_blTRUE 0.02781196 0.02756584 0.001496795
comorbidities_blTRUE 0.45975880 0.45815900 0.003210019
immunestatus_blTRUE 0.28058085 0.28144228 -0.001917349

Variance ratios

The variance ratio (VR) represents the ratio of the variance in the contracted intervention groups for each covariate. A VR close to 1, implies that variances are similar in the compared groups and as such indicates good covariate balance.

Var. Ratio
distance 0.7576281
age_cd 0.9708949
sex_cd 0.9875230
residence_area_cd731 NA
residence_area_cd732 NA
residence_area_cd733 NA
institutionalized_blTRUE NA
foreign_blTRUE NA
pregnancy_blTRUE NA
essential_worker_blTRUE NA
comorbidities_blTRUE NA
immunestatus_blTRUE NA
Var. Ratio
distance 1.0803891
age_cd 0.9802497
sex_cd 0.9590565
residence_area_cd731 NA
residence_area_cd732 NA
residence_area_cd733 NA
institutionalized_blTRUE NA
foreign_blTRUE NA
pregnancy_blTRUE NA
essential_worker_blTRUE NA
comorbidities_blTRUE NA
immunestatus_blTRUE NA

Propensity score distribution